Direct Conversion of Waste Battery Cathodes to High-Volumetric-Capacity Anodes with Assembled Secondary-Particle Morphology

The growing consumption of lithium-ion batteries calls for recycling of electrode materials. Conventional direct recycling mainly consists of cathode-to-cathode and anode-to-anode strategies. In this work, a cathode-to-anode approach is proposed using a LiCoO2 model system and extending to Co-lean/Co-free cathodes (LiNi0.8Co0.1Mn0.1O2, LiMn2O4, and LiFePO4). Commercial cathodes are featured with single-crystalline or secondary-particle polycrystalline morphology, thus exhibiting higher tap density than anodes (LiCoO2 2.7 g cm(-3) vs Si 0.25 g cm(-3)). By means of an intuitively direct conversion, the anodes are bestowed with well-assembled morphology and high tap density from cathodes. During discharging, a dual conductive network is formed to facilitate lithium storage, where the binder-derived carbon functions as electronic-conductive and LiF/Li2O as ionic-conductive motifs. Recycled cathodes exhibit an outstanding rate volumetric capacity (883 mAh cm(-3), 5 A g(-1), LiCoO2) and cyclic performance (1286 mAh cm(-3), 1000 cycles, 2 A g(-1), LiMn2O4). The morphologically inherited cathode-to-anode strategy proves to be a universal method for battery recycling toward high volumetric energy density.